Microwave Absorption Performance of Multilayer Anti-Radiation Bricks for Sustainable Construction Materials

This paper investigates the microwave absorption properties of a multilayer anti microwave cement brick. The brick incorporates polyethylene terephthalate (PET) recycled plastic with agricultural waste, palm oil fuel ash (POFA). The brick consists of three layers with varying compositions of PET $(5 \%, 10 \%$ and $30 \%$) and a constant $10 \%$ and $30 \%$ POFA (MLB1 and MLB2) as partial replacements of sand and cement respectively. Measurement is carried out for the dielectric properties and resistivity of the mixtures. The microwave absorption performance across a frequency range of 1 to 12 GHz was evaluated using the NRL Free Space Arch Method. MLB1 composition shows absorption reaching -47.98 dB at 11.66 GHz while MLB2 demonstrates consistent absorption across the entire frequency range. The compressive strength test shows MLB1 achieve average strength of 14.39 MPa. The research finding shows the developed brick can be effectively utilized in construction with electromagnetic absorption properties.